It is apparent that a need exists for supply of improved grades of nitrogen tetroxide propellants for use as oxidizers for rocket engines during system design and development tests and at the launching sites of vehicles to be projected into space, such as satellites, space shuttles, or the like. Propellant supply/oxidizer flow rate decay problems such as are prone to interfere with design/testing programs and launch scheduling of the vehicle, as well as to its space flight life duration prospects have plagued the industry. For example, the following publications report on current state of the art:
"Flow Decay in Nitrogen Tetroxide Systems", a report published at pages 7-14 of Chemical Propulsion Information Agency Publication No. 171, July 1968.
"Operational Nitrogen Tetroxide Handling", a report published at pages 41-45 of Chemical Propulsion Information Agency Publication No. 171, July 1968.
"Nitric Acid/Nitrogen Tetroxide Oxidizers", pages 2.3-1, 2.3-15, 3-26, 3-27, 3-28, 3-32, 3-33, 3-40, 3-41 and 3-45 of USAF Propellant Handbooks, Vol. II, AFRPL-TR-76-76, February 1977.
"Flow Decay", pages 101, 103, 104, 115, 117, 122, 124, 126, 132, 133, 135, 136 and 139 of Final Scientific Report, June 30, 1972, AFRPL-TR-72-84.
As a result of a professional search conducted with respect to this invention, Applicant is aware of the following U.S. Pat. Nos.: 2,298,255; 2,355,817, 2,403,932; 2,759,418; 3,095,693; 3,146,139; 3,310,444; 3,345,821; 3,383,859; 3,534,554; 3,536,543; 3,562,035; and 3,582,412. None of these references is considered relevant to the subject matter claimed herein.
Such problems are now of major concern due to the recent emergence of nitrogen tetroxide propellants as major oxidizers for liquid propellant rocket engines of such vehicles, and occur in connection with the storing, transferring, testing, launching and maneuvering operations of satellites; MX missiles; space shuttles; and the like. This is because of the tendency of such oxidizers to corrode their storage/transport/transfer containers; as well as other steel parts of the engine oxidizer supply system. Commercially available nitrogen tetroxide propellants for such purposes are typically supplied to the test site or launch-pad-mounted vehicle, either into the vehicle inboard supply tanks or into close-by "ready storage" ground-based intermediary supply relay tanks.
In either case, the supplied nitrogen tetroxide tends to react with the metal of the container and of the system components so as to cause solid precipitates of iron salts to form therefrom. Such solids in the supply stream, along with other "dirt" particulates such as are typically present in commercially supplied nitrogen tetroxide propellants, tend to plug the filters and other components of the propulsion system such as valves and injector orifices; thereby seriously interfering with the propellant transfer operations as well as the test or vehicle launching operations. Furthermore, and perhaps more importantly, the incidence thereof seriously reduces the reliable duration prospect of the rocket engine performance. Typical pre-storage and transfer/operational ambient temperature conditions contribute to these problems.